The present invention relates generally to electronic limited slip devices and associated components for use with vehicle transmissions.
FIG. 1 is a schematic drawing of a portion of a vehicle 100 having an all-wheel drive transmission 110 in which a power takeoff unit (PTU) 120 is provided for transferring power from the half shaft 102 (the shaft that extends from the differential 104 to the side shaft 106) to a propshaft 108 that is coupled to the rear vehicle axle (not shown). In such a configuration, the PTU 120 is coupled or mounted to both the engine 130 at an engine mount and to the transmission housing 112 at a transmission mount (e.g., the PTU is coupled both to the engine and to the transmission with one or more brackets 140, 142, 144 that are secured in place with fasteners such as bolts, etc.). The PTU 120 is also contained within a relatively large and heavy housing 122 that is made of a metal such as steel or aluminum. One reason for the mounting of the PTU 120 to both the engine 130 and to the transmission 110 in this manner and for the inclusion of the relatively large and bulky housing for the PTU 120 is that because of the angular relationship of the propshaft 108 to the half shaft 106, relatively significant forces (e.g., torque) are present during operation of the vehicle 100.
FIG. 2 is a schematic view of a portion of a vehicle 200 having a front-wheel drive transmission 210 utilizing an electronic limited slip device 220 (eLSD). A carrier 224 is provided around a portion of the half shaft 202 proximate the location where the half shaft 202 is coupled to the differential 204. As shown in such FIGURES, the eLSD 220 is traditionally also provided in a relatively large and heavy housing 222 that is made of a metal such as steel or aluminum similar to that shown in FIG. 1 for use with a PTU 120. This housing for the eLSD 220, similar to that illustrated in FIG. 1 for the PTU 120, is conventionally mounted both to the engine 230 and to the transmission 210 with one or more brackets 240, 242, 244 that are secured in place with fasteners such as bolts, etc. FIG. 3 illustrates a similar system as shown in FIG. 2 (with like components having similar reference numerals in the 300 series) except, for example, for the fact that the shape of the carrier 324 differs from that of the carrier 224 shown in FIG. 2 and an extra mounting bracket 346 is provided to secure the eLSD 320 to the engine 330.
FIG. 4 is a more detailed schematic view of a portion of a vehicle 400 having a front wheel drive transmission utilizing an eLSD 420. A carrier 424 is the form of a hollow member is provided around a portion of a half shaft 402 proumate the location where the half shaft 402 is coupled to the differential 404 and coupled using a splined arrangement 425. The eLSD 420 includes a housing 422 that is coupled to an engine and to the transmission. A clutch 450 of the eLSD is provided within a clutch housing 452.
One disadvantage associated with currently available vehicle transmissions that utilize eLSD systems is that the housing used to enclose the eLSD is relatively large and bulky, and takes up space that may be better used for other systems, devices, or components. Another disadvantage of such systems is that the housing must be made specifically for each vehicle or platform type so that it fits within the envelope (e.g., space) provided by the vehicle manufacturer and is compatible with the other components of the transmission. Such customization may result in inefficiencies in that the housing must be redesigned and new equipment (e.g., dies) must be created in order to manufacture the housings for each of the various vehicle programs or platforms.